There are 2 separate issues as far as I know. In the UK/EU PSN you cannot download the PS3 costumes at all.
Playstation God of War Stars Battle Bore y'all !!!
It seems this has been fixed.
I had to go back into the PS Store, select PSASBR, and where it says "Choose a Version", I had to click on the drop down menu and there was an option to redownload the previous purchase or, more importantly, a second option to add the game back into my cart for free. I added another copy of the game to my cart for free, then proceeded through the checkout. The download files for both Vita and PS3 preorder bonsues were finally included and now show in my Download List.
Thank you so much for the heads-up! I followed your steps and got the pre-order costumes.
I wanted to say thank you for this fix and bump it to the next page.
(If this doesn't work for you. I would try calling support and asking if it's an issue trying to be resolved..Hopefully, they are helpful.)
(*≧▽≦) ♪ One Night Carnival! ☆(≧▽≦*)